id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
7786	queries test failure on Python 2.3	Karen Tracey <kmtracey@…>		"Running the test suite on Python 2.3, I get a test failure in the queries regression test:

{{{
D:\u\kmt\django\trunk\tests>d:\bin\Python2.3.5\python.exe runtests.py --settings=testsettings queries
======================================================================
FAIL: Doctest: regressiontests.queries.models.__test__.API_TESTS
----------------------------------------------------------------------
Traceback (most recent call last):
  File ""d:\u\kmt\django\trunk\django\test\_doctest.py"", line 2180, in runTest
    raise self.failureException(self.format_failure(new.getvalue()))
AssertionError: Failed doctest test for regressiontests.queries.models.__test__.API_TESTS
  File ""D:\u\kmt\django\trunk\tests\regressiontests\queries\models.py"", line unknown line number, in API_TESTS

----------------------------------------------------------------------
File ""D:\u\kmt\django\trunk\tests\regressiontests\queries\models.py"", line ?, in regressiontests.queries.models.__test__.API_TESTS
Failed example:
    LoopX.objects.all()
Expected:
    Traceback (most recent call last):
    ...
    FieldError: Infinite loop caused by ordering.
Got:
    []
----------------------------------------------------------------------
File ""D:\u\kmt\django\trunk\tests\regressiontests\queries\models.py"", line ?, in regressiontests.queries.models.__test__.API_TESTS
Failed example:
    LoopZ.objects.all()
Expected:
    Traceback (most recent call last):
    ...
    FieldError: Infinite loop caused by ordering.
Got:
    []


----------------------------------------------------------------------
Ran 1 test in 0.591s

FAILED (failures=1)

}}}

I believe it's caused by this Python bug: http://bugs.python.org/issue1242657 which caused exceptions raised by !__len!__ to be silently swallowed.  A traceback from when the exception is successfully raised:

{{{

>>> LoopX.objects.all()
Traceback (most recent call last):
  File ""<console>"", line 1, in <module>
  File ""d:\u\kmt\django\trunk\django\db\models\query.py"", line 143, in __repr__
    return repr(list(self))
  File ""d:\u\kmt\django\trunk\django\db\models\query.py"", line 155, in __len__
    self._result_cache.extend(list(self._iter))
  File ""d:\u\kmt\django\trunk\django\db\models\query.py"", line 268, in iterator
    for row in self.query.results_iter():
  File ""d:\u\kmt\django\trunk\django\db\models\sql\query.py"", line 204, in results_iter
    for rows in self.execute_sql(MULTI):
  File ""d:\u\kmt\django\trunk\django\db\models\sql\query.py"", line 1598, in execute_sql
    sql, params = self.as_sql()
  File ""d:\u\kmt\django\trunk\django\db\models\sql\query.py"", line 251, in as_sql
    ordering = self.get_ordering()
  File ""d:\u\kmt\django\trunk\django\db\models\sql\query.py"", line 610, in get_ordering
    self.model._meta, default_order=asc):
  File ""d:\u\kmt\django\trunk\django\db\models\sql\query.py"", line 663, in find_ordering_name
    order, already_seen))
  File ""d:\u\kmt\django\trunk\django\db\models\sql\query.py"", line 663, in find_ordering_name
    order, already_seen))
  File ""d:\u\kmt\django\trunk\django\db\models\sql\query.py"", line 657, in find_ordering_name
    raise FieldError('Infinite loop caused by ordering.')
FieldError: Infinite loop caused by ordering.

}}}

shows how !__len!__ swallowing exceptions would cause this test failure.

Don't know that it is worth fixing (apparently you'll just get empty lists instead of exceptions in cases where this is hit) but figured it was at least worth reporting in case anyone else runs across it.  (I didn't find any likely match in my tracker search.)"		closed	Database layer (models, ORM)	dev		fixed			Accepted	0	0	0	0	0	0